The present invention is directed to scanning laser radars (LADARs), in general, and, more particularly, to a scanning LADAR with adjustable operational parameters to accommodate laser perimeter surveillance of a particular site.
Generally, in laser perimeter security systems, a scanning LADAR is disposed at a particular site for surveillance of a perimeter of the site for observing intruders seeking unauthorized access to the site. For example, a scanning LADAR may be mounted on the top of a tower at a military base or airport to scan a predetermined Field of Regard (FOR) of the perimeter thereof to render awareness of potential intruders. Other examples of site applications may include a grounded helicopter or a vehicle, like a Humvee. For the most part, these scanning LADARs include a laser which generates a beam pulsed at a repetition rate which is dependent on a maximum range. The laser is configured to scan the pulsed laser beam over a FOR generally including both an azimuth scan angle and an elevation scan angle. At each laser position in the scan, the pulsed laser beam illuminates a spot on the FOR. The scan time is the time the LADAR takes to completely scan the FOR, and the scan rate is the number of times the FOR is completely scanned per unit time. Laser return pulses from the illuminated spots on the FOR are received by the LADAR and processed according to time of flight calculations to range map the landscape of the surrounding terrain and detect intruders.
For pulsed LADAR systems in which each transmitted laser pulse can not be uniquely identified from another, pulse returns associated with each transmitted laser pulse must reach the LADAR before the next laser pulse is transmitted. This is necessary in order to prevent confusing laser pulse returns from subsequent transmitted pulses and, thus, properly perform the time of flight range mapping calculations.
Current scanning LADAR systems are manufactured with one set of operating parameters that may not be changed. The scanning laser parameters typically fixed at manufacture are the laser pulse repetition rate, the azimuth scan angle and rate and the elevation scan angle and rate. Accordingly, these scanning LADAR systems may not be able to accommodate the security and perimeter terrain surveillance requirements of the different installation sites.